Multiple signaling system



Jul 14, 1936. w. BRUCKEL 2,047,900

' MULTIPLE SIGNALING SYSTEM Original Filed May 27, 192av L llnf TRECTIFIER I I -TRANSHITTER oc RECTIFIER Inventor: Waldemar Brl'jckel,

His Attorney.

Patented July 14, 1936 UNITED STATES 2,047,900 MULTIPLE SIGNALING SYSTEMWaldemar Briickel, Berlin, Germany, assignor to General ElectricCompany, a corporation of New York Application May 27, 1929, Serial No.366,139. In Germany July 14, 1924. Renewed November 19 Claims.

My present application is a continuation in part of my formerapplication, Serial No. 40,606, entitled Multiple signaling systems,filed June 30, 1925, issued June 21, 1932, as Patent No. 1,863,829. andassigned to the same assignee as my present application;

My present invention relates to signaling systems, and more particularlyto multiplex signaling.

It is well known that a multiplex utilization of a wire signaling orremote control may be accomplished by effecting the individaul remoteoperations by alternating currents of difierent frequencies as inalternating current multiplex telegraphy. The number of connectionswhich may be established and operated without interference'over onecontinuous wire is limited by, the range of frequency which ispractically available on the particular wire. Limitations of this natureoften arise when a number of different signals are to'be transmittedover one continuous wire-from one station to several other stations. Insuch cases the total number of signals to be transmitted determines thenumber of different f so ing to the use of modulated high frequencywaves.

The high frequency waves serve to connect the transmitter with theindividual receiving stations while-the modulated frequencies serve toseparate the individual signals supplied to any one receiving stationfrom one another.

fine novel features which I believe to be charac eristic of my inventionare set forth with particularity in the appended claims.- My inventionitself, however, both as to its organization and method of operationtogether with future objects and advantages thereof will best beunderstood by reference to the following specification taken inconnection with the accompanying drawing in which Fig. 1 showsdiagrammatically a transmitter associated with a plurality oftransmission lines. Fig. 2 shows a receiving station associated with oneof the transmission lines and Fig. 3 shows certain modifications of thereceiver together with means for producing a return signal to indicatethat the transmitted signal has been properlyreceived.

Referring to the drawing, I have indicated at I a high frequencyoscillation generator or tube connected to a high frequency oscillatingoutput circuit 2 which may be adjusted for various wave lengths by meansof a plurality of condensers 3. The connection of any desired condenserwith the tube may be effected by means of relays 4. controlled from aremote point, or in any manner desired. The high frequency oscillatingtube I may be influenced in its operation by means of a specialgrid'which is connected to an additional tube or modulator 5. As in thecase of tube I, there is connected to this additional tube a lowfrequency oscillating output circuit 6 which may include condensers Iwhich are' adapted to be connected in circuit by means of relays 8.

If a relay 4 and a relay 8 are operated, a particular high frequencyoscillation is produced it is connected. All of these circuits thusoffer 20 high impedance to all of the carrier frequencies other than theone to be transmitted over the particular line. of any particularfrequency is confined to the desiredpower line over which signaling onthe respective frequency is effected, and is prevented from becomingdistributed over the other lines of the power system where it is notutilized. Thus waste of the carrier energy in extraneous channels of thepower line is avoided, and desired economy in (he transmitting equipmentis effected.

The high frequency wave produced by the transmitter reaches thecorresponding receiving station at the other end of wire II and excitesa high frequency oscillating circuit M by way of a resonant connectionl2 and inductive coupling In this way the carrier energy I3; Theseoscillations are rectified and amplified by a receiving tube I5 which iscontinuously in circuit. With pure high frequency waves, a pure directcurrent is obtained in the primary of transformer l1, while withmodulated high frequency waves a direct current with superposedalternating current of the modulation frequency is obtained there. Thedirect current component excites a relay It by which the current sourcesfor the other tubes are connected. The superposed signal bearingalternating current, on the other hand, appears in the secondary windingof transformer l1 and is supplied to the grid of the next amplifier tube18. Oscillating circuits 19 are connected in the plate circuit of tubel8 and are tuned to the individual modulation frequencies. Thesecircuits may contain the actual output relays for the circuits of theindividual intended signals. The relays may be thermal or soft ironrelays, or any type desired.

Additional rectifier tubes may be connected with the individualoscillating circuits for the purpose of converting the alternatingcurrent into direct current, andin order to make it feasible touse adirectcurrent relay as the output relay, the advantage of thisarrangement being that a very accurate and rapid effect may beobtainedwhere precise manipulations are desired. Such an arrangement isshown in Fig. 3 in which each of the tuned circuits! are shown asconnected to the input circuit of a rectifier IS, the output circuit ofwhich includes a relay 20 which may be used for signal purposes.

I have also shown in Fig. 3 of the drawing, means whereby a signal maybe transmitted back to the station including the apparatus shown in Fig.1 in response to a signal received at the receiving station.

In Fig. 3, I have represented at 2| a transmitter which is arranged tobe energized through a circuit 22 whenever any one of the relays 20 isenergized. It will be seen that this circuit is completed through themiddle contacts of any of the relays 20, these contacts all beingconnected in multiple. Also when any relay 20 is energized by means ofits upper contacts, a circuit is completed from the side of thecorresponding tuned circuit I9 opposite the connection of that circuitto ground to the modulating circuit of the transmitter 2 I, one side ofwhich may also be grounded as indicated at 23'. If this transmitter beof the type shown in Fig. 1 this connection will extend to the grid ofthe four-element discharge device which is shown connected to thecondenser 1. In this way the carrier wave which is transmitted to thesignaling station may be modulated with the same frequency whichmodulates the received carrier wave. Thus returned signals may then bereceived at the transmitting station of Fig. 1 by means 24 similarto'that shown in Fig. 2 indicating that the transmitted signal has beencorrectly received at the receiving station.

What-I claim as new and desire to secure by Letters Patent of the UnitedStates is: v

1. In a signaling system, a plurality of transmission lines adapted andarranged to transmit currents of different frequencies, a common highfrequency generator connected to all of said lines, means for varyingthe frequency of said generator thereby to supply current having any ofthe frequencies transmitted by said lines, means for modulating thecurrents supplied by said generator with any one of; a plurality ofadditional frequencies, and a receiver connected to each line,

each receiver being responsive to the frequency transmitted by therespective line, and a plurality of circuits associated with eachreceiver, each of said circuits being responsive to a different one ofsaid additional frequencies.

2. In a signaling system, a transmitter comprising a high frequencygenerator, means for varying the frequency of said generator, amodulator cooperating with said generator, means for varying thefrequency supplied by said modulator, a plurality of transmission lines,connections between said lines and said generaton'said connectionsincluding a plurality of tuned circuits, a plurality of receiversassociated with said transmission lines, said tuned circuits being tunedto wave with signal current, means included in said receiver forrectifying the received high frequency wave to obtain said signalcurrent, an amplifier for the received signal current obtained by saidlast means through rectification of the received high frequency wave andmeans for controlling the energization of said amplifier in response tothe intensity of unidirectional current resulting from the rectificationof said received high frequency wave modulated with said signal currentwhich is amplified by said amplifier.

4. In a signal system, a sending station, a remote station, means fortransmitting from the sending station a carrier wave, means forselectively modulating-said carrier wave with any one of a plurality ofdifferent predetermined frequencies, a receiver for said carrier wave inthe remote station, means associated with said receiver responsive toany of said modulations for initiating the transmission of a carrierwave back to the sending station, means for modulating saidlast-mentioned carrier wave with currents having a, frequency dependentupon the frequency of the received modulation, and means in the sendingstation responsive to said signal wave to indicate the response at theremote station.

5. In a signal system, a sending station, a remote station, means fortransmitting from the sending station a carrier wave, means forselectively modulating said carrier wave with any one of a plurality ofdifferent predetermined frequencies, a receiver for said carrier wave inthe remote station, means associated with said receiver responsive toany of said modulations for initiating the transmission of a carrierwave back I to the sending station, means for modulating said thefrequency to which the respective receivers respond, each of saidreceivers being responsive to a high frequency current of a differentfre- '7 transmitting to' said receiver a high frequency 'wave, means formodulating said high frequency last mentioned carrier wave with currenthaving the frequency of the received modulation, and means at thesending station to indicate the response at the remote station.

6. In a high frequency signaling system, a transmitting station and areceiving station, a detecting device and amplifying device in thereceiver circuit, a relay in the circuit of said detecting deviceadapted to close the power circuits for the amplifying device duringreception of the desired radio carrier wave and to open said powercircuits when no such carrier wave is being received.

7. In a high frequency signaling system, a transmitting station and areceiving station, a detecting device and amplifying device in thereceived circuit, a relay in the output of said detecting device adaptedto operate on a change in current through the detecting device when thedesired carrier wave is beingreceived and thereby control the powersupplied to the amplifying device.

' thermionic detector in the receiving circuit, am-

plifier tubes forthe output of said detector, a relay in the outputcircuit of the detector adapted to maintain the power circuitssubsequent to the detector closed during the reception of the deleastone connected with power and connecting the first named tubes to thepower source automatically upon and by the change in current in aconnectedtube due to the receipt of the radio message to be received.

11. In a radio signaling system, a radio receiving station comprisingvacuum tubes supplied with power from a local source, means forconnecting at least one of said tubes permanently to said power source,means for'connecting or disconnecting some of said tubes from said powersource, the last-named means being controlled upon and by change inspace current in a connected tube on receipt of signal current toconnect the disconnected tubes.

12. A high frequency receiver including a first portion and a secondportion, said first portion being normally in condition to. respond tohigh frequency waves and normally to supply waves resulting fromreception of said high frequency waves to said second portion, saidsecond portion being normally disconditioned for response to saidresulting waves and means responsive to the intensity of said wavesreceived in said first portion to condition said second portion forresponse to said resulting waves supplied thereto by said first portionwhenever the intensity of said waves received in said first portionexceeds a predetermined value.

13. In a high frequency signalingsystem, a

, receiving station, a thermionic detector in the receiving station, anamplifier tube for the output of said detector, means responsive toreceive high frequency waves to maintain the circuit subsequent to thedetector in operative condition during reception of the desired carrierwave and to disable said circuit upon reduction of said carrier below a,predetermined value.

14. In a high frequency signaling system, a receiver having anamplifier, said amplifier, during'desired reception of signal bearingcurrents, being in condition for normal amplification of said signalbearing currents, an electron discharge device responsive to currentsbearing the same signals as those amplified by said amplifier, and meansconnected in circuit with said electron discharge device and responsiveto said currents bearing the signals amplified by said amplifier tointerrupt operation of said amplifier injvresponse to a reduction in thelevel of received high frequency wavesto a value'above zero.

- 15. in combination, a signal receiver having a high frequency inputcircuit and an output circuit, a channel for signal bearing alternatingcurrents between said input circuit and said output circuit, meansnormally to discondition said output circuit 'for' response to saidsignal bearing currents, said means being responsive to the intensity ofcurrents received in said input circuit bearing signals to betransmitted through said channel to condition said output circuit forresponse to said currents when said intensitymined value.

an output circuit providing a signal controlled potential, meansresponsive to said potential for de-energizing said signal indicatingmeans, and means associated with said de-energizing means whereby it isrendered responsive only to signals 5 having a definite minimumamplitude.

17. The combination, in a high frequency receiver, of an input circuitupon which high frequency oscillations modulated with low frequencyoscillations are received, an output device, a transmission channelbetween said circuit and said output device, said channel includingmeans to demodulate said received high frequency oscillations toreproduce said low frequency oscillations and to supply said lowfrequency oscillations to said output device, said channel comprisingtwo portions, one of said portions being maintained continuously incondition for the transmission of current therethrough and includingmeans responsive to the intensity of said received high irequencyoscillations modulated with said low frequency oscillations which aresupplied through said channel to said output device for operating acontrol device when said intensity of the received oscillations exceedsa predetermined value, and said second portion being normallydisconditioned for the transmission of'current therethrough, and meansto condition said second portion when said control device operates.

18. The combination, in a high frequency rechannel and means aremaintained in condition for response of said output device to said lowfrequency oscillations reproduced from said received high frequencyoscillations except when said received high frequency oscillations haveintensity less than a predetermined value when said con-- dition forresponse is interrupted.

19. The combination, in a high frequency re ceiverof an input circuitupon which high frequency oscillations modulated with low frequencyoscillations are received, an output device, a channel between saidinput circuit and said output device, said output device beingresponsive to said low freqency oscillations, means in said channel todemodulate said high frequency oscillations to reproduce said lowfrequency oscillations, means to supply said reproduced low frequencyoscillations to said output device, said first means being maintainednormally in condition to demodulate said received high frequency 60oscillations and said second means being normally disconditioned fortransmission of the low frequency oscillations reproduced therefrom tosaid output device, and means responsive to the intensity of saidreceived modulated high frequency oscillations to condition said secondmeans for transmission of the low frequency oscillations reproduced bysaid first means to said output device when said intensity exceeds apredeter- WALDEMAR nniicm.

